require 'google/apis/container_v1'
require 'google/apis/cloudbilling_v1'
require 'google/apis/cloudresourcemanager_v1'

module GoogleApi
  module CloudPlatform
    class Client < GoogleApi::Auth
      SCOPE = 'https://www.googleapis.com/auth/cloud-platform'.freeze
      LEAST_TOKEN_LIFE_TIME = 10.minutes

      class << self
        def session_key_for_token
          :cloud_platform_access_token
        end

        def session_key_for_expires_at
          :cloud_platform_expires_at
        end

        def new_session_key_for_redirect_uri
          SecureRandom.hex.tap do |state|
            yield session_key_for_redirect_uri(state)
          end
        end

        def session_key_for_redirect_uri(state)
          "cloud_platform_second_redirect_uri_#{state}"
        end
      end

      def scope
        SCOPE
      end

      def validate_token(expires_at)
        return false unless access_token
        return false unless expires_at

        # Making sure that the token will have been still alive during the cluster creation.
        return false if token_life_time(expires_at) < LEAST_TOKEN_LIFE_TIME

        true
      end

      def projects_list
        service = Google::Apis::CloudresourcemanagerV1::CloudResourceManagerService.new
        service.authorization = access_token

        service.fetch_all(items: :projects) do |token|
          service.list_projects(page_token: token, options: user_agent_header)
        end
      end

      def projects_get_billing_info(project_id)
        service = Google::Apis::CloudbillingV1::CloudbillingService.new
        service.authorization = access_token

        service.get_project_billing_info("projects/#{project_id}", options: user_agent_header)
      end

      def projects_zones_clusters_get(project_id, zone, cluster_id)
        service = Google::Apis::ContainerV1::ContainerService.new
        service.authorization = access_token

        service.get_zone_cluster(project_id, zone, cluster_id, options: user_agent_header)
      end

      def projects_zones_clusters_create(project_id, zone, cluster_name, cluster_size, machine_type:)
        service = Google::Apis::ContainerV1::ContainerService.new
        service.authorization = access_token

        request_body = Google::Apis::ContainerV1::CreateClusterRequest.new(
          {
            "cluster": {
              "name": cluster_name,
              "initial_node_count": cluster_size,
              "node_config": {
                "machine_type": machine_type
              }
            }
          } )

        service.create_cluster(project_id, zone, request_body, options: user_agent_header)
      end

      def projects_zones_operations(project_id, zone, operation_id)
        service = Google::Apis::ContainerV1::ContainerService.new
        service.authorization = access_token

        service.get_zone_operation(project_id, zone, operation_id, options: user_agent_header)
      end

      def parse_operation_id(self_link)
        m = self_link.match(%r{projects/.*/zones/.*/operations/(.*)})
        m[1] if m
      end

      private

      def token_life_time(expires_at)
        DateTime.strptime(expires_at, '%s').to_time.utc - Time.now.utc
      end

      def user_agent_header
        Google::Apis::RequestOptions.new.tap do |options|
          options.header = { 'User-Agent': "GitLab/#{Gitlab::VERSION.match('(\d+\.\d+)').captures.first} (GPN:GitLab;)" }
        end
      end
    end
  end
end
